Biology subjects

Nardella, F.

Publications and source records attributed to Nardella, F..

5 recordsLinked to original sources

bioRxiv2026

Selective Disruption of Plasmodium falciparum mitochondrial DNA via G-Quadruplex-Binding Ligand RHPS4 Provides a Novel Antimalarial Strategy

Malaria caused by Plasmodium falciparum remains a major health threat, killing over 600,000 people annually. The spread of resistance to all major antimalarials, including artemisinins, highlights the urgent need for new drugs with distinct mechanisms of action. Here we show that the G-quadruplex ligand RHPS4, an acridine derivative, displays strong antiplasmodial activity against both drug-sensitive and -resistant P. falciparum strains and clinical isolates. RHPS4 primarily targets the trophozoite stage and induces major mitochondrial alterations, including reduction of mitochondrial DNA (mtDNA) and transcriptional dysfunctions. Bioinformatic analyses identified at least eight putative G4-forming sequences within the parasites mtDNA. Biophysical studies confirmed G4 folding of at least one sequence and its interaction with RHPS4. These findings indicate that RHPS4 disrupts P. falciparum mitochondrial metabolism through G4 stabilization, leading to parasite death, and establish mtDNA G4 structures as novel therapeutic targets for antimalarial development.

microbiology↗

bioRxiv2024

An all-in-one pipeline for the in vitro discovery and in vivo testing of Plasmodium falciparum malaria transmission blocking drugs

Elimination and eradication of malaria will depend on new drugs with potent activity against Plasmodium falciparum mature stage V gametocytes, the only stages able to infect the mosquito vector for onward parasite transmission. The identification of molecules active against these quiescent stages is difficult due to the specific biology of gametocyte maturation and challenges linked to their cultivation in vitro. Furthermore, the antimalarial drug development pipeline lacks a suitable animal model for evaluating the transmission-blocking potential of promising lead compounds and preclinical and clinical drug candidates in vivo. Here, we established a transmission-blocking drug discovery and development platform based on transgenic P. falciparum parasites engineered to produce large numbers of pure stage V gametocytes expressing a red-shifted firefly luciferase as reporter for cellular viability. This NF54/iGP1_RE9Hulg8 line facilitated the development of a highly efficient and robust in vitro screening assay for the identification of stage V gametocytocidal compounds. Importantly, by infecting humanized NODscidIL2R{gamma}null mice with pure NF54/iGP1_RE9Hulg8 stage V gametocytes, we also established a preclinical P. falciparum in vivo transmission model. Using whole animal bioluminescence imaging and quantification of gametocyte densities over a period of 14 days, we assessed the gametocyte killing and clearance kinetics in vivo of antimalarial reference drugs as well as five clinical drug candidates and identified markedly different pharmacodynamic response profiles. Furthermore, we successfully integrated this mouse model with mosquito feeding assays and thus firmly established a valuable tool for the systematic in vivo evaluation of gametocytocidal and transmission-blocking drug efficacy. One sentence summaryWe applied robust new assays for gametocytocidal drug discovery and in vivo efficacy testing using a humanized mouse model for malaria transmission

microbiology↗

bioRxiv2022

Quinazoline-quinoline bisubstrate inhibitors target eukaryotic translation initiation factor 3 in Plasmodium falciparum

Malaria drug resistance is hampering the fight against the deadliest parasitic disease affecting over 200 million people worldwide. We recently developed quinoline-quinazoline-based inhibitors (as compound 70) as promising new antimalarials. Here we aimed to investigate their mechanism of action by using Thermal Proteome Profiling (TPP). The eukaryotic translation initiation factor 3 (EIF3i) subunit I was identified as the main target of the inhibitor in P. falciparum. This protein is not a known drug target in malaria parasites. P. falciparum parasite lines were generated expressing either a HA tag or an inducible knockdown of the PfEIF3i gene to further characterize the target protein. PfEIF3i was stabilized in presence of the compound 70 in a cellular thermal shift-western blot assay, confirming that PfEIF3i is a target of quinoline-quinazoline-based inhibitors. In addition, PfEIF3i-inducible knock-down blocks intra-erythrocytic development in the trophozoite stage indicating that it has a vital function. We show that PfEIF3i is mostly expressed in late intraerythrocytic stages and localizes in the cytoplasm. Previous mass spectrometry reports show that EIF3i is expressed in all parasite life cycle stages. Hence, quinoline-quinazoline-based inhibitors allowed to identify PfEIF3i as a valuable target for the design of new antimalarial drugs active all along the life cycle of the parasite.

pharmacology and toxicology↗

bioRxiv2022

Hemisynthetic derivatives of the natural alkaloid trilobine are fast-acting antimalarial compounds with sustained activity in multi-drug resistant P. falciparum isolates

Malaria eradication requires the development of new drugs to combat drug-resistant parasites. The search for new chemical scaffolds that target novel pathways of the human malaria parasite Plasmodium falciparum is of highest priority. We identified bisbenzylisoquinoline alkaloids isolated from Cocculus hirsutus. (trilobine derivatives) as active in the nanomolar range against P. falciparum blood stages. Synthesis of a library of 94 hemi-synthetic derivatives allowed us to identify compound 84 that kills multi-drug resistant clinical isolates in the nanomolar range (median IC50 ranging from 35-88nM). Efforts were made to obtain compounds with significantly improved preclinical properties. Out of those, compound 125 delays the onset of parasitemia in P. berghei infected mice and inhibits P. falciparum transmission stages in vitro (culture assays) and in vivo using membrane feeding assay in the Anopheles stephensi vector. Compound 125 also impairs P. falciparum development in sporozoite-infected hepatocytes, in the low micromolar range. Finally, we used a chemical pull-down strategy to identify potential protein targets of this chemical family. Mass spectrometry analysis identified the parasite interactome with trilobine derivatives, identifying protein partners belonging to metabolic pathways that have not been previously targeted by antimalarial drugs or implicated in drug-resistance mechanisms.

pathology↗

bioRxiv2022

Humanized mice for sustained Plasmodium vivax blood-stage infection and transmission

Plasmodium vivax is the most widespread human malaria parasite 1. The presence of extravascular reservoirs 2, the early circulation of infective stages (gametocytes), and relapsing infections arising from dormant liver stages 3 render this parasite particularly difficult to control and eliminate 4. Experimental research is limited by the lack of a continuous culture in vitro system that fulfills the parasites needs,5 namely its tropism for immature CD71+ red blood cells (RBCs). 5 Here, we report a humanized mice model, which upon engraftment of human hematopoietic progenitor and stem cells (HPSCs), exhibits efficient human erythropoiesis. Humanized HIS-HEry mice inoculated with cryopreserved P. vivax samples sustain long-lasting asexual parasite multiplication within CD71+ human RBCs and differentiation into mature gametocytes that can be efficiently transmitted to Anopheles mosquitoes, leading to formation salivary-gland sporozoites. Blood stages can be sequentially transferred to uninfected humanized mice by injection of fresh or frozen infected bone marrow cells, providing a unique murine model for the long-term maintenance of P. vivax isolates. This work offers a novel experimental platform to investigate the biology of RBC invasion and intraerythrocytic P. vivax development in vivo and evaluate new interventions against this elusive human parasite.

microbiology↗